Update some documentation around ENS

Author: fselmo

docs/abi_types.rst

@@ -20,10 +20,11 @@ Ethereum Addresses
 
 All addresses must be supplied in one of three ways:
 
-* While connected to mainnet, an Ethereum Name Service name (often in the form ``myname.eth``)
 * A 20-byte hexadecimal that is checksummed using the `EIP-55
   <https://github.com/ethereum/EIPs/blob/master/EIPS/eip-55.md>`_ spec.
-* A 20-byte binary address.
+* A 20-byte binary address (python bytes type).
+* While connected to an Ethereum Name Service (ENS) supported chain, an ENS name
+  (often in the form ``myname.eth``).
 
 Disabling Strict Bytes Type Checking
 ------------------------------------

docs/middleware.rst

@@ -72,9 +72,9 @@ AttributeDict
     accept .eth names in the 'from' and 'to' fields.
 
     .. note::
-        This middleware only converts ENS names if invoked with the mainnet
-        (where the ENS contract is deployed), for all other cases will result in an
-        ``InvalidAddress`` error
+        This middleware only converts ENS names on chains where the proper ENS
+        contracts are deployed to support this functionality. All other cases will
+        result in a ``NameNotFound`` error.
 
 Gas Price Strategy
 ~~~~~~~~~~~~~~~~~~~~~~~~